What I'd like to do next is look more into this thing called love, I mean this thing called <x>, sorry, in terms of what the brackets mean and how they were appropriated into quantum mechanics by Dirac, so that we have the bra, <x|, and the ket, |x>, notation. It isn't "x" specifically that we're interested in, it's whatever symbol appears in the brackets, which may be any quantity that's being measured, such as time, t, or linear momentum, p, or whatever.
In my previous post, you can see that the brackets are used to represent the standard deviation, which in the case of the spread of error values around the average error in the measurement of time is given by the <t> expression in the lab handout. We will soon see how that expression is the same as the more commonly used shorter one that appears in the uncertainty principle classroom dream scene in A Serious Man.
But right now I'm just going to note that on this date according to my American Association of Physics Teachers' calendar, "In 1877, Thomas Edison coins telephone greeting 'Hello' instead of 'Ahoy, ahoy' supported by Alexander G. Bell."
